This has been an interesting thread! With all that math being thrown about, I was about to call for an RMA on my ADA1500 because clearly the difference I thought I heard was all in my head!

Not really...

But to get back a little bit to the original question that started all this, would it be better to upgrade the OP's sub-woofer or get a new amp?

I originally based my answer on what I heard when I added an ADA 1500 to my receiver and it made a very big difference -- much more than I expected! The OP was in a similar situation to me, with M80's and a similar receiver but a 'cheapish' subwoofer.

I can say that I often like to listen to music quite loud, and this is certainly part of the difference that I heard. I checked the owner's manual for my receiver and it claims 125 Wpc @ 8 ohms for all channels, without specifying how many channels it can really drive to this level. It also claims 'Dynamic Power' up to 170 Wpc @ 8 ohms or 270 Wpc @ 4 ohms for only two channels driven. Either way, the ADA can no doubt produce much more real power when driving my M80's!

However I don't think that is the full story, as the ADA seems to sound better even at lower volume levels, though it is not so noticeable then. I do think that the difference is not only in the bass but across all frequencies.

Now let us ask a different question: How much better would an upgraded subwoofer sound? I don't know from direct experience but it does seem to depend a bit on what the system is used to listen to and how the listener likes it to sound.

I've been trying for a fairly neutral, clear sound, which I think the Axioms largely deliver regardless of amplification options. I myself don't have a very good subwoofer, so when I set it up to blend in well with my system, it probably can't go much lower than the main speakers (M80's or LFR's) can go on their own.

After all, the M80's can produce bass down to around 30 Hz or so. My sub is only rated down to 20 Hz and at that point I think it is already down by 9 db or so. The M80's themselves are probably only down by 12-15 db at 20 Hz. So assuming the M80's are being driven full range, with my sub I may only really get a slight emphasis in the bass below 30 Hz. What's down there anyway?

In terms of music, there's not much other than tubas and pipe organs that can play below 30 Hz, and even then, when do they? I guess that a better sub might be able to reproduce better, lower explosions with more rumble, but that would only help with movies (mostly action movies) and perhaps the 1812 Overture, wouldn't it?

In terms of music, there's not much other than tubas and pipe organs that can play below 30 Hz, and even then, when do they? I guess that a better sub might be able to reproduce better, lower explosions with more rumble, but that would only help with movies (mostly action movies) and perhaps the 1812 Overture, wouldn't it?

I noticed a significant difference when i added my second EP600. I also do a decent amount of stereo listening. John told me about a couple of pipe organ CD's.. With the Dual 600's i can tell you, there is a significant amount of sound in the lower frequencies.... So, i think there is a common mis-conception that a good subwoofer "only, or mainly" benefits action movies... There are a lot of CD's that sound MUCH better in my opinion with a couple good sub's.

OK, I don't have one yet but let's agree that an Axiom subwoofer like the EP600 is a very good subwoofer. Let's also agree that having two is better than one.

Having said all that, the response of the EP600 in a typical room is flat from about 17 Hz up to 100 Hz. So when you're doing your stereo listening, I don't doubt that you're getting a lot of good sound out of your EP600s. However, how much of it is actually under 30 Hz or so? In other words, how much is actually sound that you wouldn't be able to hear out of a set of M80's?

in my own experience, having a good subwoofer that goes down very low also adds to the ambient acoustics in a recording, whether it is music or movies.take out the sub, and the ambiance is not as good, as real sounding.

However, how much of it is actually under 30 Hz or so? In other words, how much is actually sound that you wouldn't be able to hear out of a set of M80's?

This is a pretty subjective question... It depends on the music. Using a pipe organ CD, like you said, the answer to that scenario would be quite significant.

I primarily listen to classical, there is a pretty good amount of material in the lower range in classical, depending on the composer. Like J.B. said, one of the big factors is the ambient sound. This is where the experience becomes more than just numbers. Sure, the M80's play down to 30hz, with that being said. There is a HUGE difference between the impact of a sub at a given frequency as compared to a pair of towers. I would say impact is the best way to describe the difference. Before my LFR's, i used a pair of M60's for many years. When i added my first 600 it was nearly night and day.. Again, the whole experience like J.B. referring to.

I guess you could liken it to a bookshelf speaker that "plays" down to say 40hz, as compared to a tower that "plays" down to 40hz.. the tower is going to have a whole lot more impact than the bookshelf.. This is where the experience becomes more than just a numbers game... Kind of like your amp experience, on a piece of paper, there "shouldn't" have been a big difference... but the real world experience can be vastly different than the numbers on a page would sugest.

I think i am starting to ramble now... So, i am going to stop with the hopes that i answered your question. If i didn't i'll be more than happy to try again!

my former speakers, Energy 22 Pro, would go down to around 22 Hz at 75 dB SPL, but when playing loud, i would miss nearly an octave in the lows because of the box and speaker size, among other things. they could not keep up at higher power levels.

my current speakers, M80's because of box/speaker size and tuning, go lower down than the Energy when playing loud.

Frequency Response is one thing, but there is another very important thing: power response (Freq. Resp. at high power levels).

Dakkon is not the only one rambling; sometimes it's nice to be able to do that. ;-)

my former speakers, Energy 22 Pro, would go down to around 22 Hz at 75 dB SPL, but when playing loud, i would miss nearly an octave in the lows because of the box and speaker size, among other things. they could not keep up at higher power levels.

my current speakers, M80's because of box/speaker size and tuning, go lower down than the Energy when playing loud.

Frequency Response is one thing, but there is another very important thing: power response (Freq. Resp. at high power levels).

Dakkon is not the only one rambling; sometimes it's nice to be able to do that. ;-)

Exactly. 22Hz @ 75db is equivalent to the sound of a fart in the wind! Though I do believe the proper terminology is power compression rather than power response.

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